Smartphone Surface Swabs Reveal Drug Use Patterns

In a proof-of-concept study published in the April issue of Clinical Chemistry and Laboratory Medicine, researchers have demonstrated a new method to gather drug use data directly from the surface of people’s smartphones. Led by Dr. Théo Willeman from Grenoble Alpes University Hospital in France, the research aims to help healthcare providers understand which drugs are common in specific areas, as well as how and when they are used, in the hopes of improving treatments for drug overdose.

Due to the illegal nature of recreational drug use, acquiring accurate information about drug usage is challenging. More indirect methods, such as wastewater analysis or anonymous surveys of drug users paired with blood or urine analysis, are often inaccurate or too invasive for routine use.

Drawing on the ubiquitous nature of today’s smartphones, Willeman and colleagues explored the feasibility of tracking the presence of drugs on the surface of smartphones—where fingerprints that contain sweat and sebum can also contain traces of drugs.

In their study, the researchers invited people at two nightclub events in France to complete anonymous surveys on their drug use, including whether the drugs were snorted from the surface of the smartphone. They then dry swabbed all sides of the smartphones for 20 seconds before extracting and analyzing the samples via liquid chromatography with tandem mass spectrometry (LC-MS-MS).

In total, 122 swabs were collected from 122 users. The LC-MS-MS analysis revealed a variety of substances, the top three being MDMA (n=83), cocaine (n=59), and THC (n=51). Other identified substances included ketamine and LSD. Based on the declarative data from participants, the results showed the sensitivity was more than 90 percent for cocaine and MDMA but between 57 percent and 73 percent for THC, LSD, and ketamine. The specificity was more than 70 percent for all five substances, suggesting a contamination issue, wrote the researchers.

The study demonstrates the potential of smartphones as a convenient, noninvasive tool for assessing drug use in a population often difficult to reach in field research. The method is also cost effective (9 cents per swab) and easily scalable, as samples can be collected by non-specialized staff in about 20 seconds.

However, there are limitations. The method also depends in part on self-reporting from drug users, and smartphones can very well have fingerprints from multiple people on their surface. The authors also pointed out that the stability of drug molecules on the surface of smartphones and potential contamination from environmental sources could affect results.

Nonetheless, the study serves as a proof-of-concept that smartphone-swab analysis could provide a convenient and noninvasive tool for drug testing.

“The opioid crisis in the US was recognized as a public health emergency by the US President in 2016,” said Willeman in a recent press release. “As a result, developing new tools to perform toxico-epidemiology studies is crucial, and identifying which substances are consumed in a particular area may help medical teams managing potential intoxications.”